Tips for getting the best out of custom moulds

I think I will be purchasing SE535 special editions (my se530's were stolen a few months ago) and getting custom moulds. (in melbourne, australia)

I have had custom moulds twice before and have not achieved satisfactory isolation. Using them, they isolate momentarily and then come loose.

What are the factors involved in getting perfect custom moulds? Is it the quality and knowledge of the audiologist? (recommendations for Melbourne, Australia would be appreciated) Is it the factory producing the silicone inserts? Is it just the shape of my ears and my head? Are my expectations too high?

The two biggest factors will be to follow the instructions of your iem maker on the website, and to have nice clean ears (no wax) before going in. It's also worth mentioning that these are for monitors and not hearing aids as well.

Sensaphonics, the manufacturer specified by Shure say not to use a bite block... "When making ear impressions,start with your jaw open. Once the material has been injected, move your jaw to replicate the facial movements you make while performing. While the material is setting, vocalists should sing, horn players should bring a mouthpiece and play, etc." When I have had impressions done before I simply sit very still and relaxed my jaw, slightly open. This has not resulted in a good seal. And Sensaphonics also have no audiologist to recommend in Melbourne, Australia. They do in Queensland, bizarrely. I won't have time and don't want to pay again and again to get moulds that fit properly...

Sensaphonics, the manufacturer specified by Shure say not to use a bite block... "When making ear impressions,start with your jaw open. Once the material has been injected, move your jaw to replicate the facial movements you make while performing. While the material is setting, vocalists should sing, horn players should bring a mouthpiece and play, etc." When I have had impressions done before I simply sit very still and relaxed my jaw, slightly open. This has not resulted in a good seal. And Sensaphonics also have no audiologist to recommend in Melbourne, Australia. They do in Queensland, bizarrely. I won't have time and don't want to pay again and again to get moulds that fit properly...

I've been told the opposite.
Use a bite block to hold your mouth open while the material cures.
I've had 3 sets of customs done and the one that did not use the bite block had a poor seal. The ones with the bite block were fine.

As you close your mouth, the ear canal gets a little smaller so if the mold is made with your mouth open, your ear canal will clamp down a bit on the custom when your jaw is in a normal position.

exactly! conflicting information! i am inclined to try with a bite block as i have not tried one before. the people recommending a bite block appear to be getting acrylic moulds made.

are the moulds you guys have had made with silicone or acrylic?

Open mouth are supposed to be a little bigger than closed mouth impression. My audiologist told me that I should open my mouth if I want a good seal for a CIEM. I used a thick popsicle stick as a biting block. Mine was for acrylic shell. But my audiologist said to go with open mouth impressions for most uses.

As iamagloworm notes, Sensaphonics does not recommend using a bite block. And yes, we are Shure's recommended manufacturer of custom sleeves for their IEMs.

Sensaphonics has been in the business of manufacturing custom IEMs since the mid-90s, and custom earplugs long before that. Dr. Michael Santucci (founder, president, and a practicing audiologist) has developed his recommended procedure for taking impressions over the course of a lengthy career working with very demanding musicians. He actually trains other audiologists in working with musicians and taking accurate impressions, as this sort of elective equipment use (CIEMs) is not taught in university audiology curricula.

He notes that, while using a bite block when taking impression has become popular, there is no clinical evidence that using one - or not - will produce more accurate impressions. I should also point out that the earpiece material (acrylic vs silicone) is NOT a factor. (Manufacturing technique, OTOH, is a huge factor in creating properly fitting custom IEMs.)

Factually speaking, the shape of the ear canal does change with jaw/facial movement. But the WAY in which it changes (direction, degree, shape) is truly individual and not predictable. As the jaw opens, some canals get wider; others get narrower. And by varying amounts. Maddening, but clinically verifiable.

So there is no universal solution. And anyone who tells you differently is, IMHO, selling snake oil. Sorry.

As the jaw opens, some canals get wider; others get narrower. And by varying amounts. Maddening, but clinically verifiable.

So there is no universal solution. And anyone who tells you differently is, IMHO, selling snake oil. Sorry.

Correct.

I watched an interview with Jerry Harvey on the internet talking about this subject. He stated that almost 80% of people will have their ear canals wider with mouth opened whereas 20% will have it narrower. That's one of the reason why you can never guarantee a good seal. I am not sure about the numbers but it looks like it is based on his observations.

Are you not able to get a good isolation with the Yip that Shure provide?

I did get good isolation with the Shure foam tips from my se530's, I preferred the smallest size. It is with two custom moulds I have had done in the past, by two different audiologists in two different countries (australia and france) that I do not get good isolation. Both times I relaxed my jaw so my lips were together but my jaw slightly apart (as it is when relaxed)

Maybe it is as JackKontneysaid and it has more to do with the manufacture than the impression?

I read in one of the threads I linked to above that someone recommended requesting the audiologist to press the moulding material into their ear canal as much as possible...